Updating to 2.0 ruined ruined layout of site

To whom it may concern,

I just updated my website arimednow.com from version 1.7 to 2.0 and I immediately regretted it. There is now some black bar above the slider on almost every page of the website and many of the elements have disappeared from the page. However, when I check the pages and the code itself, everything is still there. Please help me or tell me how I can downgrade back to 1.7. I only need the site to be functioning and do not mind being versions behind.